Self-sealing cap for containers



Nov..17, 1931. A. A. THOMAS 1,832,669

SELF SEALING CAP FOR CONTAINERS Filed Sept. 11, 1930 2 Sheets-Sheet 1 I8 /0' 5 18: r r r 16 7 '1 I I /9 /2 1 I /3 /4 Nov. 17, 1931. A. A. THOMAS 1,832,669

SELF SEALING CAP FOR CONTAINERS Filed Sept. 11. 1930 2 Sheets-Sheet 2 gnvanfoz Patented Nov. 1% 19% ADOLJPH A. THOMAS, OF NEW YORK, N. Y.

SELF-SEALING GAP FOR GOZNTAKNERE: I

Application filed September 11, 1930. Serial No. 481,200.

flexible diaphragm or membrane which is automatically tensioned and forced lnto pres-' sure contact with the top rim of the receptacle when the cap is tightened. This pressure contact between the receptacle and the tensioned flexible diaphragm of the cap produces a sealed joint.

My new cap is characterized by simplicity of structure and consequent cheapness of manufacture. There are no loose or removable parts, and no rubber gasket is required,

as in prior caps. The practical advantages and novel features of my invention will be apparent from a description of the accom- 29 panying drawings, in which Fig. 1 shows a preferred form of my selfsealing cap, this view being in diametric section;

Fig. 2 is a sectional View of a container provided with the cap Of g- 5 Fig. 8 is a fragmentary view showing the locking ribs on the container of Fig. 2;

Fig. 4 illustrates a onepiece cap embodying my invention, this view being partly sectioned for clearness; and

Fig. 5 shows the cap of Fig. 4 in sealing position on a container.

Referring to Figs. 1 and 2, the cap structure comprises a top member 10, a cylindrical shell or body portion 12, and an elastic flexible diaphragm or membrane 13. The top member 10 is formed with a cylindrical flange 14 and a peripheral recess 15. The shell 12 has a flange 16 adapted to fit over the flange 14 of top member 10, and the-diaphragm 13 is rigidly clamped between flanges 14 and 16. In assembling the parts, the diaphragm 13 is placed over the flange 14 of member 10, and the part 12 is then driven home over the flange in a tight frictional fit. During this operation the peripheral portion 17 of the diaphragm is bent into the cylindrical space between flanges 14 and 16, which socurely hold the diaphragm in tensioned con dition. After the parts are thus assembled,

the projecting portion 18 of the outer flange 16 is bent over into the peripheral recess 15 of top member 10. The dotted outline 18 in Fig. 1 indicates the normal position of the projecting portion 18 of flange 16. The assembling of parts 10, 12 and 13 of the cap structure may be accomplished by machinery in a single operation. The shell 12 is preferably formed with a shoulder 19,

which not only limits the relative inward movement'of the shell and top member 10 during the assembling of the parts, but also cooperates with ring 15 to lock the parts against axial slipping. The top member 10 and shell 12 are preferably made of spun sheet metal (35 like aluminum or an aluminum alloy, brass, steel, and others that may be found suitable.

It is also possible to make the cap members 10 and 12 of molded material of the type represented by foremaldehyde condensation 7 products, of which bakelite is probablythe 1 most familiar. In that case, the parts 10 and 12 would be molded as a single member and the diaphragm '13 would be embedded at its periphery in the plastic material during the molding operation. This will be understood without additional illustration. The top member 10 protects the thin flexible diaphragm 13 against injury, and the intervening space 10 is sealed, so that no liquid can get into it.

The diaphragm 13 is an elastic membrane sufliciently thin to be flexible and placed un-' der tension when the cap is mounted on a container, as T shall presently explain. The diaphragm 13 is preferably made of spring metal, like steel, brass, nickel, phosphor bronze, duralumin, or other aluminum alloy,

but it may also consist of non-metallic elastic material like bakelite, celluloid, waterproof or metallized fabric, india rubber, and perhaps others. If the cap is used on receptacles containing liquid or food products. the outer surface of diaphragm 13. should be I plated or otherwise covered with a suitable substance not aflected by the contents of the receptacle. For example, if the diaphragm 13 is a disk of thin steel, it may be plated with chromium. which is impervious to atmospheric conditions and does not contamilou nate foods and liquids. If the diaphragm 13 consists of a thin elastic sheet of bakelite or similar material, no special coating will usually be necessary. It will be understood that the foregoing enumeration of materials for diaphra m 13 is not intended as a restriction or limltation of my invention, but is merely for the purpose of illustration.

The container 20 in Fig. 2 terminates in an extension 21 of considerably smaller diameter than the body of the container. When the cap is placed in sealing position on the receptacle, the top rim 22 thereof engages the diaphragm 13 along a circular line 13 and the outer annular section 13a of the diaphragm is flek'd or pulled down into slightly frusto-conical shape, whereby the central section of the diaphragm is stretched and forced into pressure engagement with the.

rim. This pressure engagement produces a sealed joint along the circular contact line 13'. It is understood, of course, that the rim 22 is sufiiciently smooth to make a fluid-tight the co-operating parts 23 and 24 constitute uii screw-threads or bayonet joints for locking the cap on the container by a rotary movement. The projecting flange 16 of the cap may be roughenedor knurled to afford a firm finger grip in turning the cap on and oii.

"Instead of a screw connection between cap and container, I may use a hinged connection of any suitable type. It is immaterial how the cover is locked in sealing position on the receptacle, provided that the diaphragm 13 is automatically tensioned and flexed to produce a sealed joint. In some instances an absolutely fluid-tight joint may not be required, and I therefore use the expression sealed joint in a practical rather than strictly technical sense.

In the modification of Figs. at and 5,,the'

cap is made of a single piece of sheet material comprising a body portion or shell 25 and a diaphragm or membrane 26, which closes one end of the shell. The most practical way of making this one-piece cap is by spinning or otherwise shaping a sheet of elastic metal into the required form, but I may also mold the cap as a single piece of bakelite. celluloid and similar material. The shell 25 is formed with screwthreads 27 adapted to engage the screwthreaded neck 28 of a suitable container 29, which s shown for illustration as a glass neaaeee jar, such as would be used for preserving fruit and the like. The jar 29 terminates in an extension 30 of reduced diameter. \Vhen the cap is screwed home on the ar, the rim of extension 30 engages the diaphragm 26 along a circular line 26 and causes the diaphragm to be flexed downwardly at the annular section 2664. This flexing of the elastic diaphragm forces the same into firm pressure engagement with the top of the ar, so that a sealed joint is formed along the circular line 26. lVhat has been said about the materials suitable for diaphragm 13 applies to diaphragm 26.

It will be observed that the elastic sealing diaphragm is normally flat (or substantially so) like a stretched membrane, and when the cap is loosened, the flexed diaphragm automatically springs back to normal position. In Figs. 1 and 2 the separate diaphragm 13 is automatically tensioned during the assembling of the parts, while in Figs. 4 and 5 the integral diaphragm 26 receives its normal tension in the spinning or shaping operation. If an' underpressure develops in the container after the cap is in sealing position, the tendency of the stretched diaphragm will be to curve inwardly, as indicated roughly at 26?; in Fig. 5, and the effect of this inward buckling of the diaphragm is to increase the pressure along the contact edge 26'. The same applies to diaphragm 13 in Fig. 2. It is not necessary that the diaphragm shall actually buckle inwardly, for in some instances there may only be a tendency of the diaphragm to do so, but even such tendency would improve the sealing of the container. The one-piece cap of Figs. 4 and 5 can be made so cheap that it is particularly adapted for household fruit jars and for containers intended to be thrown away after the contents have been re moved. Instead of making the diaphragms 13 and 26 of metal covered with a permanent plating that is not affected by the c0ntents of the receptacles, the diaphragms can be left unplated and a lining of oiled or waxed paper (and the like) interposed between the diaphragm and the rim of the container. When I therefore speak of the diaphragm being in pressure contact with the rim ofthe receptacle, I do not necessarily mean a direct contact between the two, but I also include the possibility of an interposed lining.

It will be seen from the foregoing description that I have produced a self-sealing cap of unusually simple construction, which has no loose or replaceable parts and which can be made for any size, style or shape of container. For example, my new cap may be attached to cans or jars intended to hold tobacco, coflee, tea, sugar, Hour, and other com modities used in the home. The cap is easy to keep clean, since there are no crevices where particles of food or liquid can lodge.

The sealing diaphragm 13 or 26 may vary in size from an inch or so to several inches, and even more than one foot. In fact,the larger the diaphragm, the greater will be its flexibility to establish a fluid-tight oint. The thickness and degree of flexibility of the diaphragm will naturally vary with different materials and in diflerent sizes of cap, and

, the contact line of the diaphragm, and this groove acts like a seat for the contacting surface of the container rim. I do not mean to suggest by the last statement that the diaphragm soon wears out, for it goes Without saying that it-is made of wear-resisting material that will last as long as the container itself.

Although I have shown and described oer tain specific constructions, my invention is not limited to the details set forth. Changes and modifications may be made without departing from the scope of the appended claims.

I claim as my invention:

1. A self-sealing cap for containers, comprising a cylindrical body member for engagement over the neck of a container, a top member, and an elastic diaphragm held within said body member in spaced relation to said. top member for sealing contact with the edge of the mouth portion of a container when the cap is engaged thereon. 2. A closure for containers comprising a cylindrical shellfor engagement over the neck of the container, a top member attached to said shell and closing one end thereof, and an elastic diaphragm marginally secured within said shell by said top member with the central portions of the top member and the diaphragm disposed in spaced relation, said diaphragm being disposed for engagement with the mouth edge of the container neck when the shell is engaged over the container neck.

3. A closure for containers comprising a hollow body member for engagement over the neck of the container and a top member. an elastic diaphragm Y disposed within said body member with its central portion in spaced relation to said top member and marginally secured between portions of said body member and said top member for engagementwith the mouth edge oi the container neck when the bod member is engaged over the container neck.

4. A closure for containers comprising a cylindrical shell for engagement over the neck of the container, a top member attached to said shell by a circular overlapping joint,-

and an elastic diaphragnr disposed within said shell with itscentral portion in spaced relation to said top member and marginally secured to the closure by said joint, said diaphragm being disposed for engagement with the mouth edge of the container neck when the shell is engaged over the container neck.

5. A self-sealing cap comprising a top member provided with a peripheral flange, a cylindrical shell attached to said cap, and an elastic flexible diaphragm rigidly clamped in tensioned condition between said flange and shell, said flange holding the tensioned diaphragm spaced from said top member to permit flexing of the diaphragm when the cap is mounted in sealing position on a container.

6. A self-sealing cap comprising a top member provided with a peripheral flange,

a cylindrical shell attached to said cap, an.

elastic flexible diaphragm rigidly clamped in tcnsioned condition between said flange and shell, said flange holding the tensioned diaphragm spaced from said top member to permit flexing of the diaphragm when the cap is mounted in sealing position on a container, and a shoulder formed on said shell to limit the relative inward movement of the shell and top member.

7. The combination of a container having a cylindrical exteriorly screwthrezuled portion near the top, an extension of reduced diameter above said screwthrcaded portion, a cap having a cylindrical shell engaging said screwthreaded portion to secure the cap removably on the container, and an'elastic flexible diaphragm carried by said shell to be drawn into pressure contact with the rim of said extension inwardly of the margin of the diaphragm by threading of the shell onto the screwthreaded portion of the container, whereby the diaphragm is caused to be tensioned and flexed over said rim into sealingcontact therewith.

8. The combination of a container having a cylindrical exteriorly screw'threiulcd portion near the top, an extension of reduced diameter above said screwthreaded portion, a one-piece cap having a cylindrical shell engaging said screwthreadcd portion to lock the cap removably on the container, and an elastic flexible diaphragm formed integral with said shell to be drawn into pressure con tact with the rim of said extension inwardly of the margin of the diaphragm by threading of the shell onto the screw threaded portion of the container, whereby the diaphragm is caused to be radially tensioncd and flexed over said rim into sealing contact therewith.

9. A self-sealing cap comprising a top member provided with an integral cylindrical flange at the periphery. the top of said flange being sunk relatively to the main portion of said top member to provide an annular recess, a cylindrical shell driven over said flange in a tight frictional fit, the outer peripheral edge of said shell being bent over into said annular recess, and an elastic flexible diaphragm rigidly clamped between said shell and flange, whereby said three parts are permanently connected to form a unitary cap structure in which said diaphragm is adapted to be tcnsioned and flexed into sealing contact with a container. I

10. In combination, a container inclusive of a neck or body portion and a mouth portion of less diameter than said neck or body portion forming an upward continuation of the latter, a closure inclusive or" a cylindrical portion to fit over the neck or body portion of said container, a flexible and elastic diaphragm carried by said cylindrical portion for sealing contact with the edge of the mouth portion of the container, and means for drawing the closure downward over the body portion of the container thereby to draw the diaphragm into sealing contact with the mouth edge of the container and to radially tension the diaphragm.

11. A self-sealing closure for containers comprising an elastic membrane adapted to he engaged against the edge of the mouth of the container, said membrane being of greater diameter than the mouth edge of the contairer and being formed of material sulficiently thin and elastic to be marginally flexed downward outwardly of its circular line of contact with the mouth edge of the container and to thereby have its central portion tensioned thus to form a tight seal of the membrane against the mouth edge of the container, and means for marginally drawing the membrane downward and for radially tensioning the same when the membrane is engaged against the mouth edge of the container.

ADOLPH A. THOMAS.

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